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| | 3 | Nigel sent along a series of plots based on MD04 stack tests. I do not fully agree with his interpretation of these plots. First, his plot of the stack image sky sigma (based on the pixel data) with exposure time looks fine. This shows that as more images are combined, the resulting image sigma also increases as the square root of the exposure time. This is what we should expect. |
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| | 5 | [[Image(md04deep_v2_sigmaplot_scaled.png,400px)]] |
| | 6 | |
| | 7 | The next plot is where we disagree. This plot shows the mean pixel sky level divided by the number of input warps for the stack, as a function of the number of input warps. Number of input warps scales with exposure time of the final stack, so the x-axis on this plot is in large part just a proxy for the sky sigma of the image. |
